Simulated Drought Conditions Research Articles

Scrutinizing harsh habitats endophytic fungi and their prospective effect on water-stressed maize seedlings.

Drought constitutes a significant abiotic stressor that hinders plant growth and productivity in many countries. Habitat-adapted endophytic fungi offer an environmentally sustainable approach to address this issue by promoting plant development and enhancing resilience against abiotic stresses. In this study, 30 endophytic fungal isolates were recovered from some wild plants in the extreme habitats of Port Said Governorate, Egypt, and evaluated for their drought tolerance using polyethylene glycol (PEG-6000). Only eight isolates demonstrated drought tolerance properties and were further evaluated for their plant growth-promoting biochemical activities and ability to improve maize germination under simulated drought conditions. All eight isolates exhibited enzyme activity for endo-1,4-β-glucanase, amylase, and pectinase, and most displayed significant nutrient mobilization, with siderophores production ranging from 4 to 89%, ammonia production from 1 to 7μmol/ml, and phosphate solubilization from 129to 256µg/ml. Additionally, all isolates showed strong antioxidant activity and high total phenolic content, with some also producing notable levels of indole acetic acid (IAA) and gibberellic acid (GA3) as plant growth hormones. Coating maize grains with spore suspensions of the eight fungal isolates, in general, significantly increased their germination parameters and seedling vigor in vitro under 8% PEG-6000. This enhancement was particularly pronounced with Neurospora sitophila (P8L4M1) and Penicillium tardochrysogenum (P15L4M1), which increased the vigor of maize seedlings by approximately 308% compared to untreated control. Molecular identification of P8L4M1 and P15L4M1 was performed by amplifying the 28S rRNA gene. This study disclosed unique endophytic fungal isolates with promising potential for enhancing drought resistance in maize.

Screening of Ecotypes and Construction of Evaluation System for Drought Resistance during Seed Germination in Kudouzi (Sophora alopecuroides)

Drought is a major limiting factor in the cultivation of Sophora alopecuroides in China’s arid and semi-arid regions. This study aimed to identify drought-resistant S. alopecuroides ecotypes and explore key drought tolerance indicators during germination by simulating drought conditions with a 10% PEG-6000 solution, using pure water as a control. Determination of seven germination indicators for S. alopecuroides, including germination rate (GR), germination energy (GE), germination index (GI), vigor index (VI), promptness index (PI), fresh weight (FW), and dry weight (DW), was conducted. Principal component analysis (PCA), membership function, cluster analysis, and linear regression were employed to comprehensively evaluate the drought resistance of thirty-five S. alopecuroides ecotypes. The results showed that drought stress caused reductions in six of the seven indicators across all ecotypes, except for DW, compared to the control. Correlation analysis revealed varying relationships among the indicators, with most showing significant or highly significant correlations. PCA reduced the seven indicators to two independent comprehensive factors, with a cumulative contribution rate of 83.99%. Based on the D-value and cluster analysis, the thirty-five ecotypes were ranked for drought resistance and classified into four categories. The top five drought-tolerant genotypes during the germination stage were identified as Yutian, Alar, Jinghe, Baoding, and Guyuan. Moreover, the stepwise regression model was established and demonstrated that GR, GE, PI, FW, and DW are key indicators for screening and identifying drought-resistant S. alopecuroides ecotypes. This study offers a comprehensive and reliable method for evaluating drought resistance in S. alopecuroides ecotypes and provides a reference for selecting ecotypes for artificial cultivation in Northwestern China.

Escape rooms: behavioural response of two invasive crayfish species under water decline scenarios

Climate change and invasive alien species pose a significant threat to biodiversity and the survival of native species. This study considered the impact of drought conditions on the escape behaviour through terrestrial dispersal ability of two invasive freshwater crayfish species, the red swamp crayfish (Procambarus clarkii) and signal crayfish (Pacifastacus leniusculus). Using an experimental design simulating drought conditions and Mediterranean summer temperatures, we tested the hypothesis that P. clarkii exhibits a greater tendency to terrestrial migration and a higher land-walking speed than the P. leniusculus. The results indicated that both species demonstrated strong escape behaviour, with P. clarkii showing escape success higher than P. leniusculus, and increasing with decreasing mean night temperature and crayfish weight. Although drought conditions did not trigger escape, invasive species showed increased resistance and the ability to move to more favourable environments, suggesting that drought is not an effective geographic barrier against the spread of these species. These results underline the importance of considering invasive species' ability to escape and climb as part of management and control strategies.

Response of salt intrusion in a tidal estuary to regional climatic forcing

Salinity distribution in a large tidal estuary is subject to estuarine adjustment under the influences of multiple physical drivers such as freshwater pulses and sea level rise, and is crucial to upstream water quality, aquaculture, and ecosystem functions of the estuary. To better understand the estuarine salinity response to climate change, the unstructured-grid Finite Volume Community Ocean Model was implemented to simulate the salt intrusion in the Delaware Bay Estuary. The model was first validated by multiple observational data sets and subsequently applied in an idealized setting to examine the response of salt front to freshwater pulses in high flow conditions, followed by a long-term drought condition supported by a multi-decadal streamflow drought analysis in the estuary. The model results showed that after the freshwater pulses the salt front location moved further upstream with sea level rise. Under the simulated long-term drought condition, the adjustment timescale of salt intrusion varies nonlinearly with sea level rise. With a significant increase in sea level rise, the adjustment timescale starts to decrease. This shift suggests a transition into a different regime where the estuary becomes more stratified, as indicated by an increasing bulk Simpson number with rising sea levels.

ВПЛИВ ОБРОБКИ НАСІННЯ МЕТАБОЛІЧНО АКТИВНИМИ РЕЧОВИНАМИ НА АКТИВНІСТЬ АСКОРБАТПЕРОКСИДАЗИ ТА ВМІСТ АСКОРБАТУ В ПРОРОСТКАХ ПШЕНИЦІ М’ЯКОЇ (TRITICUM AESTIVUM L.) ЗА УМОВ ВОДНОГО ДЕФІЦИТУ

The article presents a comparative analysis of the effects of metabolically active substances and their combinations on ascorbate peroxidase activity and ascorbate content in common wheat (Triticum aestivum L.) seedlings under water deficit conditions simulated using PEG 6000. Ten seed treatment options were studied: control (unprocessed seeds + distilled water); PEG 6000 solution (12 %); vitamin E solution (10-8M) – E; ubiquinone-10 solution (10-8M) – Q; methionine solution (0.001 %) – M; paraoxybenzoic acid (POBA) solution (0.001%) – P; MgSO4 solution (0.001%) – Mg; combinations: vitamin E (10-8M) + ubiquinone-10 (10-8M) – EQ; vitamin E (10-8M) + methionine (0.001 %) + POBA (0.001 %) – EMP; vitamin E (10-8M) + methionine (0.001 %) + POBA (0.001 %) + MgSO4 (0.001 %) – EMPMg. The experimental water deficit was simulated using a 12 % PEG 6000 solution. It was found that simulated drought conditions induced a 63.1% increase in ascorbate peroxidase activity compared to the control. Pretreatment of wheat seeds with compound E resulted in a 65.5 % increase in ascorbate peroxidase activity compared to the control and a 2.4 % increase compared to seedlings under simulated water deficit conditions using PEG 6000. The activity of ascorbate peroxidase in wheat seedlings after treatment with magnesium sulfate, ubiquinone-10, and the combination of vitamin E + ubiquinone-10 exceeded control values by 47.6 %, 35.7 %, and 31 %, respectively, but did not surpass the levels induced by PEG. This suggests a protective effect of these substances under water deficit conditions but does not completely mitigate the inhibitory effect of PEG 6000. Under simulated water deficit conditions, the accumulation of ascorbate in seedling tissues exceeded control values by 29.1 %. Treatment with ubiquinone-10 increased ascorbate content by 46.3 %, while treatment with a combination of vitamin E + methionine + POBA + MgSO4 increased it by 24.2 %. Other treatments also showed increases: vitamin E + methionine + POBA (18.8 %), methionine (13 %), and vitamin E + ubiquinone-10 (7.4 %). Pre-treatment of wheat seeds with metabolically active substances increased the activity of antioxidant enzymes in wheat seedlings, enhancing drought resistance in the Provintsialka variety. Therefore, seed treatment with these substances could serve as a component of grain crop cultivation technology under water deficit conditions.

Exogenous Sodium and Calcium Alleviate Drought Stress by Promoting the Succulence of Suaeda salsa.

Succulence is a key trait involved in the response of Suaeda salsa to salt stress. However, few studies have investigated the effects of the interaction between salt and drought stress on S. salsa growth and succulence. In this study, the morphology and physiology of S. salsa were examined under different salt ions (Na+, Ca2+, Mg2+, Cl-, and SO42-) and simulated drought conditions using different polyethylene glycol concentrations (PEG; 0%, 5%, 10%, and 15%). The results demonstrate that Na+ and Ca2+ significantly increased leaf succulence by increasing leaf water content and enlarging epidermal cell size compared to Mg2+, Cl-, and SO42-. Under drought (PEG) stress, with an increase in drought stress, the biomass, degree of leaf succulence, and water content of S. salsa decreased significantly in the non-salt treatment. However, with salt treatment, the results indicated that Na+ and Ca2+ could reduce water stress due to drought by stimulating the succulence of S. salsa. In addition, Na+ and Ca2+ promoted the activity of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), which could reduce oxidative stress. In conclusion, Na+ and Ca2+ are the main factors promoting succulence and can effectively alleviate drought stress in S. salsa.

The Cooperation Regulation of Antioxidative System and Hormone Contents on Physiological Responses of Wedelia trilobata and Wedelia chinensis under Simulated Drought Environment.

Drought-induced metabolic dysregulation significantly enhances the production of reactive oxygen species (ROS), which, in turn, exerts a substantial influence on the oxidation-reduction regulatory status of cells. These ROS, under conditions of drought stress, become highly reactive entities capable of targeting various plant organelles, metabolites, and molecules. Consequently, disruption affects a wide array of metabolic pathways and eventually leads to the demise of the cells. Given this understanding, this study aimed to investigate the effects of different drought stress levels on the growth and development of the invasive weed Wedelia trilobata and its co-responding native counterpart Wedelia chinensis. Both plants evolved their defense mechanisms to increase their antioxidants and hormone contents to detoxify ROS to avoid oxidative damage. Still, the chlorophyll content fluctuated and increased in a polyethylene-glycol-simulated drought. The proline content also rose in the plants, but W. chinensis showed a significant negative correlation between proline and malondialdehyde in different plant parts. Thus, W. trilobata and W. chinensis exhibited diverse or unlike endogenous hormone regulation patterns under drought conditions. Meanwhile, W. trilobata and W. chinensis pointedly increased the content of indole acetic acid and gibberellic acid in a different drought stress environment. A positive correlation was found between endogenous hormones in other plant parts, including in the roots and leaves. Both simulated and natural drought conditions exerted a significant influence on both plant species, with W. trilobata displaying superior adaptation characterized by enhanced growth, bolstered antioxidant defense mechanisms, and heightened hormonal activities.

Influence of induced drought on photosynthetic performance in Dactylis glomerata varieties during the early growth stage

Drought significantly impacts the growth and yield of forage grasses, particularly its effect on Dactylis glomerata photosynthetic apparatus during the initial phase of development remains largely unknown. This study investigated the effects of drought on physiological parameters of various D. glomerata varieties. The seedlings obtained after seed germination under optimal and simulated drought conditions by PEG 6000 (three variants) were planted in small pots filled with garden substrate. Over a span of 42 days, the plants were initially kept well-watered (70% capillary water capacity, CWC), after which half of the seedlings from each variant were subjected to drought. This drought stress was applied during the tillering phase for 12 days. Subsequently, the plants were rehydrated (at 70% CWC) and allowed to recover for 14 days. Throughout both drought and recovery periods, measurements were taken. Leaf chlorophyll fluorescence parameters were assessed, and the JIP-test analysis was utilised to provide detailed insights into the functionality of D. glomerata photosynthetic apparatus under drought stress and post-recovery conditions. Several parameters were identified as indicative of the plants’ sensitivity to drought, such as performance indices PI ABS and PI tot, along with quantum yield parameters Ψ E0, φ E0, and φ P0. The results highlighted that var. Minora and Tukan exhibited greater tolerance to water deficit when compared to the other varieties studied. They showed a large increases in PIABS and PItot values after drought stress as well as after the re-watering (recovery period) compared to control plants. This suggests their potential for better adaptation to drought conditions.

Co-expression network analysis reveals PbTGA4 and PbAPRR2 as core transcription factors of drought response in an important timber species Phoebe bournei.

Phoebe bournei is one of the main afforestation tree species in subtropical regions of China and is famous for its timber. Its distribution and growth are significantly impaired by water conditions. Thus, it is essential to understand the mechanism of the stress response in P. bournei. Here, we analyzed the phenotypic changes and transcriptomic rearrangement in the leaves and roots of P. bournei seedlings grown for 0 h, 1 h, 24 h, and 72 h under simulated drought conditions (10% PEG 6000). The results showed that drought stress inhibited plant photosynthesis and increased oxidoreductase activity and abscisic acid (ABA) accumulation. Spatio-temporal transcriptomic analysis identified 2836 and 3704 differentially expressed genes (DEGs) in leaves and roots, respectively. The responsive genes in different organs presented various expression profiles at different times. Gene co-expression network analysis identified two core transcription factors, TGA4 and APRR2, from two modules that showed a strong positive correlation with ABA accumulation. Our study investigated the different responses of aboveground and belowground organs of P. bournei to drought stress and provides critical information for improving the drought resistance of this timber species.

Using Recycled Construction Waste Materials with Varying Components and Particle Sizes for Extensive Green Roof Substrates: Assessment of Its Effects on Vegetation Development

Using construction waste materials as substrates can reduce the resource consumption of minerals and provide sustainability benefits in green roofs. This research examined the viability of crushed bricks and crushed concrete with varying particle sizes as substrates by conducting a simulated drought experiment and roof experiment. Six composite substrates were prepared, respectively, by mixing peat with small-, medium-, and large-sized crushed bricks and crushed concrete particles (peat-to-inorganic-particle volume ratio of 1:2). The properties of each group were within acceptable parameters, with the crushed brick substrates displaying lower bulk density and higher porosity compared to the crushed concrete substrates. Seldom lineare was selected for the experiments, and the substrate thickness was set at 10 cm. Under the simulated drought conditions, the growth and stress resistance of Seldom lineare in the crushed brick substrates was similar to that in the conventional substrates and poorer in the crushed concrete substrates. Seldom lineare in medium-particle-size brick substrates performed the best, surpassing the traditional group. The growth of Seldom lineare in the small-particle-size concrete substrates was the worst. In the rooftop environment, all groups could support Seldom lineare over 180 days without maintenance, with an overall coverage of more than 60%. The plants in the medium-particle-size brick substrates exhibited the highest cover. In conclusion, the medium-particle-size brick substrate exhibits ideal characteristics in terms of substrate physical properties and plant growth, making it a favorable option.

Drivers of wood decay in tropical ecosystems: Termites versus microbes along spatial, temporal and experimental precipitation gradients

Abstract Models estimating decomposition rates of dead wood across space and time are mainly based on studies carried out in temperate zones where microbes are dominant drivers of decomposition. However, most dead wood biomass is found in tropical ecosystems, where termites are also important wood consumers. Given the dependence of microbial decomposition on moisture with termite decomposition thought to be more resilient to dry conditions, the relative importance of these decomposition agents is expected to shift along gradients in precipitation that affect wood moisture. Here, we investigated the relative roles of microbes and termites in wood decomposition across precipitation gradients in space, time and with a simulated drought experiment in tropical Australia. We deployed mesh bags with non‐native pine wood blocks, allowing termite access to half the bags. Bags were collected every 6 months (end of wet and dry seasons) over a 4‐year period across five sites along a rainfall gradient (ranging from savanna to wet sclerophyll to rainforest) and within a simulated drought experiment at the wettest site. We expected microbial decomposition to proceed faster in wet conditions with greater relative influence of termites in dry conditions. Consistent with expectations, microbial‐mediated wood decomposition was slowest in dry savanna sites, dry seasons and simulated drought conditions. Wood blocks discovered by termites decomposed 16–36% faster than blocks undiscovered by termites regardless of precipitation levels. Concurrently, termites were 10 times more likely to discover wood in dry savanna compared with wet rainforest sites, compensating for slow microbial decomposition in savannas. For wood discovered by termites, seasonality and drought did not significantly affect decomposition rates. Taken together, we found that spatial and seasonal variation in precipitation is important in shaping wood decomposition rates as driven by termites and microbes, although these different gradients do not equally impact decomposition agents. As we better understand how climate change will affect precipitation regimes across the tropics, our results can improve predictions of how wood decomposition agents will shift with potential for altering carbon fluxes. Read the free Plain Language Summary for this article on the Journal blog.

Genetic diversity in maize at germination and seedling stages under simulated drought conditions

Ninety seven maize (Zea mays) genotypes were evaluated for germination and early seedling characters under PEG6000 (8%) induced drought stress to identify drought tolerant genotypes. Descriptive statistics for percentage of seed germination and abnormal seedling, shoot length, root length, and shoot dry weight, root dry weight, seedling length, seedling dry weight, and vigor index revealed significant variation among the genotypes studied. The percentage of germination and abnormal seedlings varied greatly among the genotypes. The first and second principal components (PC) of PCA results accounted for 73.15 and 26.85% of the total variation of maize genotypes, respectively. The first PC variation consisted primarily of relative seedling shoot dry weight and relative seedling root dry weight. Cluster analysis grouped the genotypes into four clusters. Cluster III genotypes performed better in terms of relative shoot dry weight, relative root dry weight, and number of abnormal seedlings, indicating drought tolerance. Very poorly performance was shown by genotypes in cluster IV, whereas moderately performance was shown by genotypes in cluster II and I. The clusters differed significantly from one another, according to D2 and multivariate analysis. Thirty six genotypes viz. BD-814, BD-810, BD-812, BD-821, BD-815, BD-10015, BD-10238, CML-552, BD-822, BD-826, CML-341, CML-555, CML-591, CML-523, CML-564, BD-817, BD-10018, BD-10240, CML-577, CML-342, CML-556, BD-837, CML-544, BD-827, BD-806, BD-835, BD-840, BD-842, BD-10010, CML-562, BD-10239, BD-10016, CML-593, CML-568 and BD-10234 demonstrated relatively drought tolerance during the germination and early seedling stages might be used in future breeding program. Ann. Bangladesh Agric. (2023) 27 (2): 19-30

Combating Drought Stress Anomalies in Grain Quality of Phaseolus vulgaris: Role of Soil Amendments

ABSTRACT Phaseolus vulgaris is one of the most widely consumed legumes across the globe. It is rich in protein, carbohydrates, fiber, bioactive compounds, and mineral contents. Occurrences of drought under changing climate have posed a challenge to the quality and quantity of the crop yield. Our study, taking Phaseolus vulgaris as a test legume, reports that as a soil amendment, biochar and farmyard manure mitigated drought-induced damage in the plant. The experiment was set up in a greenhouse with 1 m2 blocks together arranged in factorial randomized block design. Water withdrawal was done for 15 days in either vegetative or reproductive stage of the crop to simulate drought conditions. Biochar or Farmyard manure was applied at the rate of 10t ha−1 as soil amendment and each treatment was replicated thrice. Higher photosynthesis (up to 23% and 16%, respectively), leaf protein (41% and 30%, respectively), grain protein (4% and 19%, correspondingly), and in-vitro protein digestibility (60% and 254%, respectively) were noted under application of both the amendments. Grain quality in terms of protein content, in-vitro protein digestibility, and protein fractions of Phaseolus vulgaris was improved under drought due to the addition of biochar and farmyard manure. However, the application of those amendments at the rate of 10t ha−1, especially farmyard manure, had a negative impact on the antinutritional factor (phytic acid) and mineral bioavailability. Between the two amendments studied, farmyard manure proved to be more efficient in promoting the overall grain quality of P. vulgaris, but its inimical effects must be concorded.

Soil legacy and organic amendment role in promoting the resistance of contaminated soils to drought

The application of organic amendments is a common practice in the restoration of contaminated and degraded soils. We designed an experiment in pot mesocosms to study the effect of organic amendment (comparing a short-term addition of biosolid compost with soils amended 17 years ago) and soil legacy (comparing soils exposed or not to extensive grazing over a remediation process) on the resistance of a degraded Mediterranean soil against a simulated drought event. Pots were sown with a forage mixture (Lolium rigidum and Medicago polymorpha), and soil resistance was evaluated by measuring soil chemical properties, biological activity (soil enzyme activities and respiration rate), soil microbial community composition and plant production. Our results showed a positive effect of the organic amendment and the exposure to extensive grazing on soil properties, increasing soil water retention and the stability of plant production under drought conditions. The long-term amendment addition avoided the negative consequences of drought on L. rigidum production (the species with the lowest tolerance to water stress), while M. polymorpha biomass in soils exposed to grazing was 12 times the biomass in the non-amended and non-exposed soil. However, soil biological activity (enzyme activities and respiration rate) as well as microbial diversity were not limited by the simulated drought conditions under any type of soil management legacy, demonstrating the great adaptation of the microbial communities to water stress conditions in semiarid Mediterranean soils. Soils exposed to organic matter inputs in the long-term, through amendment addition or exposure to grazing, showed high similarities in terms of bacterial and fungal composition.

Metal Accumulation and Tolerance of Energy Willow to Copper and Nickel under Simulated Drought Conditions

The aim of this study was to determine the effect of drought on the accumulation and tolerance of energy willow (Salix viminalis L. var. ‘Gigantea’) to copper (Cu) and nickel (Ni) in the context of phytoremediation potential of the plant and biomass production under adverse water conditions. Drought was simulated with polyethylene glycol (PEG-6000. 5%), and metals were added at a concentration of 1 mM. Plants were cultivated in greenhouse conditions for 21 days according to the experimental variants: control, Cu, Ni, PEG, PEG + Cu and PEG + Ni. The results indicate high toxicity of Cu (chlorosis, necrosis, decrease in biomass, plant dehydration, increase in the content of proline and phenolic compounds), and PEG + Cu co-treatment increased the toxicity of the metal. Ni applied at the same concentration did not cause toxicity symptoms. The willow exhibits the ability to accumulate Ni, and mutual application of PEG + Ni increased Ni uptake to new shoots. Cu caused elevated accumulation of proline and phenolics in leaves accompanied with a decreased carbon and nitrogen content in roots in favor of young shoots. Both metals and drought led to disruption in the content of mineral nutrients (Ca, Mg, Fe). Due to high tolerance to Ni and drought, S. viminalis var. ‘Gigantea’ bears high potential for biomass production on Ni-polluted sites with accompanying metal uptake increased under water deficit.

Effect of PEG-6000 Osmoticum on Seed Germination and Seedling Growth of Lentil (Lens culinaris Medik.) Genotypes

Background: Drought, extreme temperatures, salinity, chemical toxicity and oxidative stress are such environmental stresses, that are serious threats to agriculture globally and result in the deterioration of the environment and crops. To Study the effect of drought stress on seed germination and early establishment in different crop varieties, PEG (Polyethylene Glycol) induced drought stress is the most common screening method. The species and its variety, its growing conditions and the developmental stage of the plant, as well as osmotic concentration responded differently to osmotic stress. The current study aimed to study the effect of different concentrations of PEG-6000 in eight genotypes of lentil in order to understand the management and control of drought stress-related problems in crop plants. Methods: The experimental work was conducted during 2018-2019 at the Laboratory of Botany, S.S. Jain Subodh P.G. (Autonomous) College, Jaipur to study the effect of drought stress during early growth of genotypes of Lentil (Lens culinaris Medik.) under osmotic stress. The plant material consisted of eight genotypes belonging to the macrosperma and microsperma subspecies of lentil (Lens culinaris M.). PL-4, L-4147, L-4594 and L-4596 belong to the microsperma subspecies and K-75, L-4076, DPL-15 and DPL-62 belong to the macrosperma subspecies. Result: In conclusion, due to their better values of germination percentage (GP%), germination relative index (GRI), seedling vigor index (SVI) and seedling growth under simulated drought conditions PL-4, L-4594, DPL-15 and DPL-62 stand out as the most tolerant lentil genotypes among eight species studied in this work. These genotypes showed a significant enhancement in germination percentage (%), germination relative index, seedling vigor index and seedling length under mild moisture stress. Our results confirmed that PEG-induced drought stress can be used to study the drought-tolerant species by studying a few parameters viz. germination percentage, germination relative index and, seedling vigour index, that will result in increased crop production.

EVALUATION OF COTTON GENOTYPES SEEDLINGS FOR DROUGHT STRESS TOLERANCE

The present studies clearly indicated that expressivity of some of the genes was changed due to the simulated drought conditions. The root increases in length in response to drought thus utilizes more photosynthates changing the sink and ultimately reducing the shoot growth. The shift due to drought indicated that the growth and morphological development of root system are under genetic control but may be modified by environmental influences. To screen out drought tolerant and drought susceptible genotypes on the basis of morphological seedling traits such as root characters and root / shoot length ratio. After screening, three drought tolerant genotypes namely BH-124,149-F and DPL-26 and three drought susceptible genotypes i.e. CIM-446, FH-945 and VH-28 were identified which may be used in further hybridization programme to develop drought tolerance varieties and hybrids.

Mesoporous silica nanoparticle-induced drought tolerance in Arabidopsis thaliana grown under in vitro conditions.

Nanoparticles of varying formats and functionalities have been shown to modify and enhance plant growth and development. Nanoparticles may also be used to improve crop production and performance, particularly under adverse environmental conditions such as drought. Nanoparticles composed of silicon dioxide, especially those that are mesoporous (mesoporous silica nanoparticles; MSNs), have been shown to be taken up by plants; yet their potential to improve tolerance to abiotic stress has not been thoroughly examined. In this study, a range of concentrations of MSNs (0-5000mgL-1) were used to determine their effects, in vitro, on Arabidopsis plants grown under polyethylene glycol (PEG)-simulated drought conditions. Treatment of seeds with MSNs during PEG-simulated drought resulted in higher seed germination and then greater primary root length. However, at the highest tested concentration of 5000mgL-1, reduced germination was found when seeds were subjected to drought stress. At the optimal concentration of 1500mgL-1, plants treated with MSNs under non-stressed conditions showed significant increases in root length, number of lateral roots, leaf area and shoot biomass. These findings suggest that MSNs can be used to stimulate plant growth and drought stress tolerance.

Physiological indicators of water metabolism in plants of parental forms and F1hybrids ofG. Barbadense L. cotton type under different water supply conditions

This article presents the findings of an extensive research endeavor aimed at comprehending the physiological intricacies of water metabolism in novel strains of fine-fiber cotton belonging to the species Gossypium barbadense L. These strains include L-2006, L-167, L-5440, L5445, L-1, L-10, L-663, and L-450, alongside the standard variety Surkhan14 and its F1 hybrids. The study was conducted under various water regime conditions to unravel the responses of these cotton genotypes to different levels of water availability. Upon analysis, it was discerned that the physiological parameters of water metabolism exhibited dynamic changes across the studied genotypes of fine-staple cotton. Specifically, when confronted with simulated soil drought conditions, the water content and transpiration intensity of leaves demonstrated varying degrees of reduction. This response was contingent upon the individual characteristics of each genotype. Furthermore, a noteworthy trend emerged: the water-retaining capacity of leaves displayed an increase under water stress conditions. This observed rise in water-retaining capacity in the leaves can be considered a vital physiological mechanism. It’s a mechanism that contributes to the adaptation of fine-staple cotton to water stress. These findings offer valuable insights into the strategies employed by fine-fiber cotton genotypes to cope with water scarcity. By shedding light on the interplay between physiological responses and water availability, this research provides a foundation for informed decision-making in cotton breeding, agricultural management practices, and the cultivation of drought-resistant cotton varieties.

Screening Bambara Groundnut (Vigna subterranea L. Verdc) Genotypes for Drought Tolerance at the Germination Stage under Simulated Drought Conditions.

Bambara groundnut (Vigna subterranean L. Verdc) is grown by smallholders and subsistence farmers in the marginal parts of sub-Saharan Africa. This legume is native to Africa and is cultivated throughout semi-arid sub-Saharan Africa. It is hardy and has been recognized as a nutritious food source in times of scarcity. Drought can negatively affect the germination or establishment of seedlings in the early stages of crop growth. Drought can limit the growing season of certain crops and create conditions that encourage the invasion of insects and diseases. Drought can also lead to a lack of crop yield, leading to rising food prices, shortages, and possibly malnutrition in vulnerable populations. A drought-tolerant genotype can be identified at the germination stage of Bambara groundnut by screening for drought-tolerance traits, and this knowledge can be applied to Bambara crop improvement programs to identify drought-tolerant traits during early growth phases. As an osmolyte, polyethylene glycol (PEG 6000) reduced water potential and simulated drought stress in Bambara groundnut seeds of different genotypes. Osmolytes are low-molecular-weight organic compounds that influence biological fluid properties. In this study, 24 Bambara groundnut genotypes were used. Data were collected on seed germination percentage (G%), germination velocity index (GVI), mean germination time (MGT), root dry mass (RDM), root fresh mass (RFM), and seven drought tolerance indices: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), stress susceptibility index (SSI), yield index (YI), yield stability index (YSI), stress tolerance index (STI) as well as seed coat color measurements. The data were applied to the mean observation of genotypes under simulated drought conditions (Ys) and the mean observation of genotypes under controlled conditions (Yp). Germination%, germination velocity index (GVI), mass germination time (MGT), and root fresh mass (RFM) differed significantly (p < 0.001) between the two stress conditions. Bambara genotypes Acc 82 and Acc 96 were found to be the most drought-tolerant.